1. Field of the Invention
The present invention relates to a magnetic head slider that prevents a magnetic head element from degrading over a long period by suppressing transmission of vibrations to the magnetic head element.
2. Description of the Related Art
Conventionally, a magnetic disk apparatus is utilized as a storage device that reads and writes information repeatedly in various systems such as a computer, a personal computer, and a server. A magnetic head slider that is used to read information from a magnetic disk in the magnetic disk apparatus, usually has a magnetic head element configured of a GMR (giant magneto resistive) element and utilizing a giant magneto-resistance effect, or configured of a TMR (tunneling magneto resistive) element and utilizing a ferromagnetic tunneling effect.
Such a conventional magnetic head slider will be briefly explained below with reference to FIG. 14. FIG. 14 is a schematic diagram of a positional relationship between a magnetic disk DK and a magnetic head slider 9. As shown in FIG. 14, a slider main body 11 of the magnetic head slider 9 is supported by a suspension 12. A magnetic head element 13 is positioned at a distal end (the right side in FIG. 14) of the slider main body 11 to record and reproduce data recorded on the magnetic disk DK, which rotates at a high speed.
In the magnetic head slider 9 having the above configuration, when the magnetic head element 13 is used over a long period, the GMR element or the TMR element constituting the magnetic head element 13 degrades, and an output thereof gradually reduces due to the degradation, thereby leading to a data read error.
As shown in FIG. 14, the magnetic head slider 9 is slightly levitated from the magnetic disk DK. Recently, however, a gap t between the magnetic head slider 9 (the magnetic head element 13) and a surface of the magnetic disk DK is being gradually reduced to increase a recording density.
Specifically, a recording density of a recent magnetic disk is high, and a levitation amount of a magnetic head is about 10 nanometers. Although a magnetic disk is desirably flat, its face is actually finely undulated. When a levitation amount is reduced to about 10 nanometers, the magnetic disk and the magnetic head come in contact with each other, due to fine undulation on the magnetic disk, at a time of reading data from the magnetic disk, thus the former receives an impact from the latter. Consequently, even if a magnitude of the impact due to the contact between the magnetic head and the magnetic disk is minute, the life (degradation) of the magnetic head element is affected by vibrations due to the contact.
The present inventor has found that, when a magnetic head slider equipped with such a magnetic head element as a GMR element is used under a condition of receiving vibrations, an output from the magnetic head element gradually reduces after prolonged use of the magnetic head slider. The inventor has disclosed a quantitative evaluating method based on prediction of a life of a magnetic head element (see Japanese Patent Application Specification No. 2004-335080).
According to the evaluating method, a magnitude of an impact due to contact between the magnetic head element and the recording medium (a magnetic disk DK) is detected, and a life of the magnetic head is predicted based on the magnitude of the impact detected. Therefore, the life of the head can be predicted properly even when the head and the recording medium frequently come in contact with each other due to reduction in a levitation amount of the head.
Japanese Patent Application Laid-Open No. 2000-322713 discloses a conventional technique regarding the degradation of a thin film magnetic head element. According to this technique, a face opposite to a GMR element is covered with a crystallization preventing film made of a shield layer, to thereby prevent degradation of the magnetic head element.
In the life predicting method for a head as described in Japanese Patent Application Specification No. 2004-335080, life of a magnetic head element can be predicted properly, but actually, when the magnetic head element is used over a long period, it is necessary to avoid or reduce a drawback due to contact with a magnetic disk DK (degradation clue to vibrations).
In the countermeasure of covering the face opposite to the GMR element with the crystallization preventing film made of a shield layer, described in Japanese Patent Application Laid-Open No. 2000-322713, when the magnetic disk DK and the magnetic head slider actually come in contact with each other, propagation of vibrations to the magnetic head element due to the contact can not be prevented effectively. Accordingly, degradation of the magnetic head element over a long period cannot be prevented.